Conventional methods of reinforcing earth include grading the substrate that supports the reinforced earth and adding additional layers of fill and perhaps other materials. The fill may be soil, crushed stone or waste. Such layers experience shear with respect to one another, particularly when the substrate is graded to a slope or is adjacent to a hillside. Efforts to compensate for and overcome such shear include use of various geotextile fabrics which absorb shear and also act as filters between layers. Conventional geotextile fabrics typically lack sufficient tensile strength to absorb great shear loads found in applications such as walls of waste pits, embankments, and applications on slopes, however.
One previous approach to forming a high-strength layer between fill layers in earth reinforcement applications is to install expanded plastic sheets. Such sheets are formed of relatively thick plastic typically two millimeters or greater in width. The sheets are alternately and periodically sliced and then pulled transverse to the slices to form a grid with diamond-shaped interstices. The strength axis of such grids is parallel to the slices, and this axis is placed down-slope or in the direction in which strength is required. Such grids have proved to be expensive to manufacture, difficult to connect to adjacent grids, and otherwise difficult, labor intensive and expensive to package, transport and install, particularly in cold weather when the plastic stiffens.